Azure DTU Calculation

Question

We have some DB instances on Azure, I am trying to optimize DB Performance on Azure. Can any explain what is Azure DTU & How can we calculate Azure DTU ?

Answer 1

The significant consideration of the Azure SQL Database is to meet the performance requirement of the deployed database against the minimum cost. Undoubtedly, nobody wants to pay money for the redundant resources or features that they do not use or plan to use.

At this point, Microsoft Azure offers two different purchasing models to provide cost-efficiency:

Database Transaction Unit (DTU)-Based purchasing model. Virtual Core (vCore)-Based purchasing model A purchasing model decision directly affects the database performance and the total amount of the bills. In my thought, If the deployed database will not consume too many resources the DTU-Based purchase model will be more suitable.

Now, we will discuss the details about these two purchasing models in the following sections.

Database Transaction Unit (DTU)-Based purchasing model In order to understand the DTU-Based purchase model more clearly, we need to clarify what does make a sense DTU in Azure SQL Database. DTU is an abbreviation for the “Database Transaction Unit” and it describes a performance unit metric for the Azure SQL Database. We can just like the DTU to the horsepower in a car because it directly affects the performance of the database. DTU represents a mixture of the following performance metrics as a single performance unit for Azure SQL Database:

CPU Memory Data I/O and Log I/O

Elastic Pool Briefly, Elastic Pool helps us to automatically manage and scale the multiple databases that have unpredictable and varying resource demands upon a shared resource pool. Through the Elastic Pool, we don’t need to scale the databases continuously against resource demand fluctuation. The databases which take part in the pool consumes the Elastic Pool resources when they are needed but they can not exceed the Elastic Pool resource limitations so that it provides a cost-effective solution.

Properly Estimation of the DTU for Azure SQL Database After deciding to use DTU-based purchase model, we have to find out the following question-answer with logical reasons:

Which service tier and how much DTUs are required for my workload when migrating to Azure SQL? DTU Calculator will be the main solution to estimate the DTUs requirement when we are migrating on-premise databases to Azure SQL Database. The main idea of this tool is capturing the various metrics utilization from the existing SQL Server that affects the DTUs and then it tries to estimate approximately DTUs and service tier in the light of the collected performance utilizations. DTU calculator collects the following metrics through the either Command-Line Utility or PowerShell Script and saves these metrics to a CSV file.

Processor - % Processor Time Logical Disk - Disk Reads/sec Logical Disk - Disk Writes/sec Database - Log Bytes Flushed/sec

Extracted from https://www.spotlightcloud.io/blog/what-is-dtu-in-azure-sql-database-and-how-much-do-we-need.

Check this well-written article on calculating DTU

Credit to original author : Esat Erkec

Answer 2

1.What is Azure DTU:

Azure SQL Database provides two purchasing models: vCore-based purchasing model and DTU-based purchasing model.

DTU-based purchasing model is based on a bundled measure of compute, storage, and IO resources. Compute sizes are expressed in terms of Database.Transaction Units (DTUs) for single databases and elastic Database Transaction Units (eDTUs) for elastic pools.

The Database Transaction Unit (DTU) represents a blended measure of CPU, memory, reads, and writes. The DTU-based purchasing model offers a set of preconfigured bundles of compute resources and included storage to drive different levels of application performance: Basic, Standard and Premium.

For more details, please see: https://learn.microsoft.com/en-us/azure/sql-database/sql-database-service-tiers-dtu

2.How to optimize DB Performance:

Since your DB instances are already on Azure, you can monitor your DB instances and improve your DB Performance with Azure Portal by troubleshot or change the service tiers. Please see: Monitoring and performance tuning: https://learn.microsoft.com/en-us/azure/sql-database/sql-database-monitor-tune-overview#improving-database-performance-with-more-resources

3.How to calculate Azure DTU:

Here is a link about Azure SQL Database DTU Calculator.This calculator will help us determine the number of DTUs for our existing SQL Server database(s) as well as a recommendation of the minimum performance level and service tier that we need before we migrate to Azure SQL Database. If you still keep the database backup file, i think you can try this calculator.

Please see: http://dtucalculator.azurewebsites.net/